1. Field of the Invention
The present invention relates to a system and a method of controlling a continuously variable valve lift apparatus. More particularly, the present invention relates to a system and a method of controlling a continuously variable valve lift apparatus which can implement non-excessive response of a variable valve lift apparatus.
2. Description of Related Art
Internal combustion engines generate power by receiving and burning air and fuel in a combustion chamber. When air is sucked, an intake valve is operated by a camshaft, and air is sucked into the combustion chamber while the intake valve is open. Further, an exhaust valve is operated by the camshaft, and air is discharged from the combustion chamber while the exhaust valve is open.
The optimum operation of the intake valve/exhaust valve, however, depends on the RPM of the engine. That is, an appropriate time for lifting or valve opening/closing depends on the RPM of the engine. In order to implement an appropriate valve operation in accordance with the RPM of the engine, as described above, a VVL (Variable Valve Lift) apparatus and a CVVL (Continuously variable Valve Lift Apparatus) which have a plurality of shapes of cam operating valves or operating valves at different lifts in accordance with the RPM of an engine have been studied.
A CVVL engine can reduce pumping loss and implement an optimum valve lift with the engine load in the intake stroke. Further, the CVVL engine can reduce the time for filling a surge tank and directly control the amount of intake air by varying the valve lift. Therefore, the CVVL engine can achieve quick response.
The quick response of the CVVL engine may turn out to be excessive response in overdriving and the excessive response may interfere with stable driving.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.